One of my future goals is to go NFA, and naturally that brings into play a 300 blackout build.

I've seen videos of shooting suppressed, but of course almost anything recorded while shooting tends to overload youtube sound.

What is the difference between shooting 300 Blackout sub sonic (with a suppressor) and say 5.56 in terms of noise. If possible can you relate to real world noise levels. I know dB system, but I don't have a lot of experience with 100 dB vs 110 dB or 40 vs 100db.

Javelin

12-24-11, 11:12

Next to each other - to a bystander that knows nothing and hearing the 300BLK using a 762SD side-by-side to a 5.56 using M4-2000?

The 300BLK will sound like almost Hollywood quiet vs the 5.56 which will still sound loud (just not hurt your ears loud).

That's the simplest way to put it.

Spooky130

12-24-11, 13:22

Next to each other - to a bystander that knows nothing and hearing the 300BLK using a 762SD side-by-side to a 5.56 using M4-2000?

The 300BLK will sound like almost Hollywood quiet vs the 5.56 which will still sound loud (just not hurt your ears loud).

That's the simplest way to put it.

Exactly... You never realize how loud the sonic crack is of a 5.56 until you put a suppressor on one. Amazing how loud that little bullet is...

Eurodriver

12-24-11, 16:00

http://i41.tinypic.com/105ac8k.jpg

Just wanted to whore this image a bit.

The 2nd from bottom rifle is a Noveske 300 BLK.

I pretty much echo what was said above. Hollywood quiet.

The 5.56 suppressed is freakin sweet, don't get me wrong. With ear plugs you don't hear the sonic crack so all thats heard is a little "thush" but remove the ear pro and the sonic crack is definitely audible. To people unfamiliar with suppressors they give you the "Wtf? I thought it was a SILENCER" look...

Ironman8

12-24-11, 16:07

I realize the OP specifically asked for 300BLK subs VS 5.56 (no specification), but to compare subs to supers is apples and oranges. I would be more interested in how the sound differs with both shooting supersonic since there has yet to be a "good" subsonic round made as far as terminal ballistics go....any comments in that regard?

I realize the OP specifically asked for 300BLK subs VS 5.56 (no specification), but to compare subs to supers is apples and oranges. I would be more interested in how the sound differs with both shooting supersonic since there has yet to be a "good" subsonic round made as far as terminal ballistics go....any comments in that regard?

supers in both sound very similar to me. 30 cal cans tend to be larger than 556 cans and so often have a slightly more pleasing lower tone.

SomeOtherGuy

12-28-11, 08:55

I heard them back to back at a suppressor demo and as others have said, the subsonic 300BLK is very quiet, while the supersonic 5.56 is just somewhat reduced from normal loud.

I realize the OP specifically asked for 300BLK subs VS 5.56 (no specification), but to compare subs to supers is apples and oranges. I would be more interested in how the sound differs with both shooting supersonic since there has yet to be a "good" subsonic round made as far as terminal ballistics go....any comments in that regard?

Apples and oranges maybe, but I don't know of any viable subsonic 5.56 loads - anything that's even available or will cycle the action. And there have been a number of deer and some hogs taken with subsonic 300BLK that appear to have been taken cleanly. It's more like a big handgun wound than like the wound from a bullet going over 2000fps, but it appears to do the job.

Quiet Riot

12-28-11, 14:24

The 300BLK supersonic burns its powder more efficiently than the 5.56, especially in shorter barrels. So, it seems to meter better when suppressed and is "hearing safe" from most cans. That doesn't mean you actually want to shoot it without hearing protection, but according to the dBs, a suppressor is still a BIG help on supersonics (including 5.56).

There is no serious reason to compare 5.56 and 300BLK subsonics. Only the 300BLK platform can reliably cycle with both supers and subs with no adjustments whatsoever, and a suppressed 300BLK sub is crazy quiet.